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At least 397 records · Page 22Linked to original sources
PubMed1984

Presynaptic, muscarinic inhibition of non-adrenergic, non-cholinergic neuromuscular transmission in the chicken rectum.

Cholinergic inhibition of the non-adrenergic, non-cholinergic ( NANC ) transmission was investigated in the chicken isolated rectum with Remak's nerve attached. Stimulation of Remak's nerve (RT stimulation) at frequencies higher than 5 Hz elicited a late, slow contraction of the rectum in addition to an initial, fast NANC contraction. The late, slow contraction was blocked by atropine (0.25 microgram ml-1), potentiated by physostigmine (50 ng ml-1) and accompanied by an overflow of acetylcholine into the vascular perfusate, indicating the existence of cholinergic innervation to the rectum via Remak's nerve. RT stimulation (10 pulses at 0.5-1.0 Hz) elicited NANC -mediated excitatory junction potentials (e.j.ps). The e.j.p. amplitude declined at the second stimulus and then increased to reach a plateau. Atropine, by abolishing this decrease in amplitude, increased the mean amplitude of the e.j.ps during trains of stimuli but atropine did not affect the amplitude of the first e.j.p. Physostigmine reduced the mean e.j.p. amplitude, and this action was readily antagonized by atropine. A single intramural nerve stimulation delivered 2s or less before RT stimulation with trains of stimuli, suppressed the amplitude of the first e.j.p. of the train. This effect was abolished by atropine. Atropine in concentrations high enough to affect the e.j.p. amplitude had no effect on the resting membrane potential, the threshold for generating an action potential, or membrane resistance of the smooth muscle. It is concluded that RT stimulation at low frequencies causes the release of acetylcholine simultaneously with the NANC transmitter. The released acetylcholine acts mainly on prejunctional muscarinic receptors and mediates an inhibitory effect on the release of the NANC transmitter.

Acetylcholine↗
PubMed1988

Development before and after hatching of non-cholinergic excitatory innervation to the rectum via Remak's nerve in the fowl.

1. Development of the excitatory innervation to the rectal region of the intestine via Remak's nerve has been investigated in the rectum with Remak's nerve supply isolated from chicken embryos and young chicks aged less than two weeks. 2. Electrical stimulation of Remak's nerve produced a small contraction of the rectum isolated from chicken embryos on the 14th day of incubation (the earliest time examined). The contractile response was inhibited partially or totally by atropine (0.1 micrograms ml-1) but enhanced by physostigmine (0.01 to 0.05 micrograms ml-1), indicating its cholinergic nature. 3. During the embryonic stage, the proportion of the atropine-resistant component in the contractile response increased, and the contractile response became almost entirely atropine-resistant within the first week after hatching. 4. Later after hatching, the contractile response was increased in magnitude by atropine and reduced by physostigmine. 5. It is concluded that the excitatory innervation to the chicken rectum via Remak's nerve is cholinergic at the 14-16th day of incubation and is gradually replaced by a non-cholinergic innervation during embryonic development.

Animals↗
PubMed1988

The sympathetic innervation of the internal anal sphincter and rectum in the cat.

The distribution of the sympathetic innervation to the internal anal sphincter (IAS) and rectum and the occurrence of different types of adrenergic receptors in the two organs were investigated in anaesthetized cats. Anal pressure and rectal motility were recorded by a manometric and a volumetric method respectively. Division of both the hypogastric nerves (HGN) and the lumbar colonic nerves (LCN) reduced the anal pressure by 46 +/- 6% of the resting pressure (40.9 +/- 6.4 mmHg) and consistently increased rectal motility. Efferent electrical stimulation of the HGN as well as the LCN elicited a contraction in the anus and the rectum, which, at maximal stimulation, caused the anal pressure to reach a similar level to that recorded before division of these nerves. After injection of phentolamine the anal contraction was abolished, whereas the rectal contraction was either abolished or converted to a beta-adrenergic relaxation. Propranolol caused increased rectal contraction in response to stimulation of the HGN and the LCN, whereas the anal contraction was unaffected. The results imply that the sympathetic nerves exert a tonic excitatory effect on the IAS and a dual effect on the rectum in the cat. The results also indicate that sympathetic fibres to the IAS are conveyed in both the HGN and the LCN. Inhibitory beta-adrenergic receptors seem to be of minor importance in regulating anal pressure.

Adrenergic Fibers↗
PubMed2006

A deformable image registration method to handle distended rectums in prostate cancer radiotherapy.

In image-guided adaptive radiotherapy, it is important to have the capability to automatically and accurately delineate the rectal wall, which is a major dose-limiting organ in prostate cancer radiotherapy. As image registration is a process to find the spatial correspondence between two images, a major challenge in intensity-based deformable image registration is to deal with the situation where no correspondence exists for some objects between the two images to be registered. One example is the variation of rectal contents due to the presence and absence of bowel gas. The intensity-based deformable image registration methods alone cannot create the correct spatial transformation if there is no correspondence between the source and target images. In this study we implemented an automatic image intensity modification procedure to create artificial gas pockets in the planning computed tomography (CT) images. A diffusion-based deformable image registration algorithm was developed to use an adaptive smoothing algorithm to better handle large organ deformations. The process was tested in 15 prostate cancer cases and 30 daily CT images containing the largest distended rectums. The manually delineated rectums agreed well with the autodelineated rectums when using the image-intensity modification procedure.

Algorithms↗
PubMed1970

The action of sennosides and related compounds on human colon and rectum.

The direct action of intraluminal senna and related compounds on the human colon and rectum has been investigated. Motility was recorded by balloon kymography with recording units inserted into well established transverse colostomies or into the rectum. The motility of the colon was not changed by intraluminal senna glycosides but the introduction of senna previously incubated with faeces or Esch. coli stimulated the colon to peristalt. The peristalsis was similar to that stimulated by rheinanthrone, an oxanthrone produced by chemical hydrolysis and reduction of senna. Both activated senna and rheinanthrone appeared to act in the colon by contact stimulation. No peristaltic response was stimulated in the rectum, either with activated senna or with rheinanthrone.

Anthraquinones↗
PubMed1971

Mucosubstances in neoplasms of the human colon and rectum.

The patterns of mucosubstances secreted in the normal human colon and rectum, in benign tumours, and in and around malignant tumours of the colon and rectum have been studied. Very little neutral mucosubstance was seen in normal specimens; the secretion in these was made up of sulphated and nonsulphated acid mucosubstances, with the former predominating in the deeper half and the latter in the superficial half of the mucosa.Benign tumours contained moderate amounts of mucosubstance, predominantly acid nonsulphated mucosubstances. Differences in the pattern of secretion were observed between the adenomatous polyp on the one hand and the villous papilloma and the papillary parts of the papillary adenoma on the other. Carcinomas of colon and rectum contained very little secretion, with very scanty or no evidence of sulphation. The mucosa around carcinomas and in areas of non-polyploid hyperplasia in carcinoma-bearing colons showed two constant patterns, one consisting of very small amounts of secretion, with sulphated mucosubstance predominating, and the other showing normal or increased amounts of secretion almost entirely of the acid nonsulphated variety. The latter pattern extended for several centimetres from the tumour. The possibility that sulphated mucosubstance might have a role in controlling cell division and that a decrease in its secretion might initiate a sequence of changes leading to malignancy is discussed.

Adult↗
PubMed1990

Evidence for motor neuropathy and reduced filling of the rectum in chronic intractable constipation.

Subtotal colectomy with ileorectal anastomosis is now frequently offered to patients with slow transit constipation who have severe symptoms and no response to more conventional medical treatment. If this operation is to be successful, the underlying problem should be delay in the progress of contents through the colon but no mechanical or functional obstruction in the small bowel or rectum. We have used a recently described technique of prolonged ambulant manometry and electromyography to investigate anorectal function in these patients. Pressure data were collected using a 2 mm diameter intrarectal probe carrying microtransducers, and external anal sphincter activity was assessed by a pair of silver-silver chloride surface electrodes. Fourteen control subjects and eight patients with colonic inertia were studied. Sampling reflexes, indicative of rectal filling, occurred at mean (SEM) rates of 7.4 (2.0)/hour in controls but were significantly reduced in patients (2.4 (0.3)/hour (p less than 0.01]. Recurrent rectal motor complexes were seen to occur in both groups at intervals of 76 (1.8) minutes in controls and 64.9 (7.2) minutes in patients (p less than 0.1), and with amplitudes of 42.4 (2.1) mmHg and 9.2 (0.7) mmHg (p less than 0.001), respectively. External sphincter electromyographic spike activity did not differ between groups. Our results support the concept of reduced transit of faeces to the rectum from the colon over a 24 hour period in slow transit constipation and suggest that a motor neuropathy may also be present in the rectum.

Adult↗
PubMed2003

Molecular and functional studies of electrogenic Na(+) transport in the distal colon and rectum of young and elderly subjects.

BACKGROUND: Human distal nephron and distal colon both exhibit mineralocorticoid sensitive electrogenic Na(+) absorption and make significant contributions to Na(+) homeostasis. Na(+) resorption in the distal nephron diminishes with age but it is unclear whether a similar change occurs in the distal colon. AIMS: To evaluate the effect of age on expression of apical Na(+) channels and basolateral Na(+), K(+)-ATPase, and on the responsiveness of electrogenic Na(+) absorption to mineralocorticoid stimulation in human distal colon and rectum. MATERIALS AND METHODS: Mucosal biopsies were obtained from healthy sigmoid colon and proximal rectum in "young" (aged 20-40 years) and "old" (aged 70 years or over) patients during routine colonoscopy/flexible sigmoidoscopy. Na(+) channel subunits and Na(+), K(+)-ATPase isoforms were studied at the mRNA level by in situ hybridisation and northern blotting, and at the protein level by immunocytochemistry and western blotting. The mineralocorticoid responsiveness of electrogenic Na(+) absorption was evaluated in the two groups by measuring amiloride sensitive electrical potential difference (PD) in the proximal rectum before and 24 hours after oral administration of 1 mg of fludrocortisone. RESULTS: Na(+) channel subunit and Na(+), K(+)-ATPase isoform expression at the level of mRNA and protein was similar in "young" and "old" patients. Both basal and the fludrocortisone stimulated amiloride sensitive rectal PDs were similar in the two groups. CONCLUSIONS: In contrast with the distal nephron, mineralocorticoid sensitive electrogenic Na(+) absorption in the human distal colon does not diminish with age, and may be particularly important in maintaining Na(+) homeostasis in the elderly.

Absorption↗
PubMed1994

Comparative evaluation of ovarian structures in cattle by palpation per rectum, ultrasonography and plasma progesterone concentration.

The aims of this study were to determine the relationship between the ultrasonographic determination of corpora lutea and the plasma progesterone profile of cyclic cows during an oestrous cycle, and to compare the accuracy of detection of normal and abnormal ovarian structures by ultrasonography and palpation per rectum, based on the plasma progesterone profile. The ovaries of six lactating cyclic dairy cows were scanned and blood samples were obtained three times a week for one month. There was a high correlation (r = 0.85) between the diameter of the corpus luteum and the plasma progesterone concentration, but on days -3 and -2 (oestrus = day 0) the diameter was the same as mid-luteal values but it was functionally inactive (plasma progesterone < 0.5 ng/ml). The accuracy of palpation per rectum and ultrasonography for determining the presence and age of the corpora lutea was investigated in 34 cows by using the plasma progesterone concentration and the dissection of ovaries post mortem as standards. The sensitivity, specificity and positive predictive value of palpation for identifying mid-cyclic corpora lutea were 85 per cent, 95.7 per cent and 89.5 per cent, respectively. Ultrasonography had a sensitivity of 95 per cent, a specificity of 100 per cent and a positive predictive value of 100 per cent. Twenty-nine cows were diagnosed by palpation per rectum as having either follicular or luteal cysts. During ultrasonography, an ovarian cyst was defined as a non-echogenic structure at least 5 mm in diameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Barium enema examination following biopsy of the rectum or colon.

A four-component study was designated to evaluate the possible risk of perforation during barium enema examination following biopsy of the rectum or colon. The study included a survey of gastrointestinal radiologists, an in vitro study of pig colons after biopsy, colon pressure measurements in human subjects, and histological analysis of human colonoscopic biopsy specimens. The results suggest that superficial biopsy of the rectum of colon performed with small colonoscopic forceps is a safe procedure and no waiting period is necessary before performing a barium enema study. However, biopsy of the colon or rectum with proctoscopic forceps appears to have greater potential for perforation and a waiting period between biopsy and barium enema study is recommended. Radiologists should distinguish between proctoscopic and colonoscopic biopsy procedures before determining when a barium enema study will be performed following biopsy.

Animals↗
PubMed1998

Regional and transmural density of interstitial cells of Cajal in human colon and rectum.

The interstitial cells of Cajal (ICC) are thought to play an important role in the control of gut motility. The regional and transmural pattern of distribution of ICC in the normal human colon and rectum was evaluated with immunohistochemistry using an anti-c-kit antibody. The transmural distribution of ICC was constant throughout the whole colon, the density of ICC was significantly greater at the myenteric plexus than at either the longitudinal or circular muscle layers, and in the rectum the transmural distribution was more even. Regionally, at the myenteric plexus, the transverse colon had a significantly greater density of ICC compared with the right colon (P = 0.038), left colon (P = 0.006), and rectum (P = 0.008). The pattern of distribution of ICC identified in this study is consistent with the proposed roles of ICC as colorectal pacemakers, intermediaries of the neural control of muscle activity, and coordinators of colorectal muscle activity. The highest density of ICC was at the myenteric plexus of the transverse colon, which is the proposed region of pacemaking activity.

Adult↗
PubMed1977

The location and mechanism of hyperosmotic fluid secretion in the rectum of the saline-water mosquito larvae Aedes taeniorhynchus.

1. Ligation between the anterior and posterior segments of the rectum in vitro was used to demonstrate that the posterior rectum is the site of hyperosmotic secretion to the lumen side. Observations were consistent with a reabsorptive function for the anterior rectum. These results support predictions from ultrastructural studies of these two segments. 2. The initial potential of the rectal lumen, relative to the haemocoel side, was of opposite polarity in the anterior (-10 mV) and posterior (+ 10 mV) segments and these values decreased to -2 and +6 mV respectively in ligated recta which had secreted for 2 h. 3. A comparison of these potential difference measurements with concentration differences developed across the rectal epithelium under the same experimental conditions indicates that Na+, K+, Mg2+, and Cl- are all actively transported by the posterior segment to the lumen side. 4. The influence of different haemolymph concentrations of Na+, K+, and Cl- on the potential differences across the basal cell border and across the whole rectal epithelium are reported. Based on this and previous data, we propose a model for the organization of transport processes within the single celltype present in the posterior rectal epithelium.

Aedes↗
PubMed1987

The amino acid sequence of a smooth muscle-contracting peptide from chicken rectum. Identity to chicken neurotensin.

Previous studies have demonstrated that chicken rectum contains a peptide which exerts a potent, excitatory action on the smooth muscle of chicken rectum, and this peptide is most likely to be chicken neurotensin isolated recently from chicken small intestine. In the present study, the peptide was extracted from 2 kg of chicken rectums, and then it was isolated by gel filtration, ion exchange chromatography, high voltage paper electrophoresis and HPLC. Amino acid analysis of the peptide revealed that it is a tridecapeptide composed of aspartic acid (Asp), glutamic acid (Glu), proline (Pro), alanine (Ala), valine (Val), isoleucine (Ile), two residues of leucine (Leu), tyrosine (Tyr), histidine (His), lysine (Lys) and two residues of arginine (Arg). Its amino acid sequence was determined to be pGlu-Leu-His-Val-Asn-Lys-Ala-Arg-Arg-Pro-Tyr-Ile-Leu-OH. The molecule is identical to chicken neurotensin.

Amino Acid Sequence↗
PubMed1981

Effect of X irradiation on the rectum of the rat.

It is demonstrated how a definite part of the rectum of the female Wistar rat can be selectively irradiated without surgery. The effect of X irradiation on the rectum is in the acute phase (second week after irradiation) a haemorrhagic radiation proctitis and in the chronic phase a rectal obstruction. The dose-effect relationship using rectal obstruction as the end point is a sigmoid curve with a ED10 of 17.50 Gy, ED50 of 21.5 Gy and ED90 of 27.5 Gy. Latency time decreases exponentially with increasing dose and is 150 days at the ED50. Histological findings show mucosal glands and cysts within the submucosa and a severe submucosal radiation within the submucosa and a severe submucosal radiation fibrosis which results in the rectum becoming a rigid and non-elastic tube which leads to a functional block in transport of faeces.

Animals↗
PubMed2006

Resection of asynchronous quadruple advanced colonic carcinomas followed by reconstruction with ileal interposition between the transverse colon and rectum.

We report an extremely rare case of resectable asynchronous quadruple advanced colonic carcinomas. Successful reconstruction was performed after resection with an ileal interposition between the remaining colon and rectum, and the patient recovered bowel function. Resections of the four colonic lesions in three operations allowed us to leave a portion of the large bowel and to thereby preserve the rectum and a portion of the transverse colon. After resection of the third and fourth cancer lesions, we reconstructed the large bowel with ileal segment interposition between the residual transverse colon and rectum, leaving a 15-cm-long segment portion of the transverse colon. This surgical procedure is an option for reconstruction after left-sided colectomy.

Adenocarcinoma↗
PubMed1989

Possible role of plasma neurotensin in regulating the excitatory neural control of the rectum of the fowl.

Effects of neurotensin (NT) applied via the blood vessel on the responses to stimulation of Remak's nerve (RNS) were investigated in the chicken isolated and perfused rectums. NT (5 ng-2 micrograms/ml) produced a concentration-dependent inhibition of the constituent contraction but not relaxation of the responses to RNS. In addition, high concentrations of NT (over 80 ng/ml) produced a contraction of the rectal muscle. Propranolol, a beta-adrenoceptor blocking agent, and guanethidine, an adrenergic neurone blocking agent, were able to reduce the inhibitory effect of NT on the response to RNS while potentiating the contractile effect of NT on the rectal muscle. NT (0.1 and 1 microgram/ml), like norepinephrine, decreased the flow rate of perfusate from the isolated rectum which was perfused at a constant pressure. Guanethidine enhanced norepinephrine-induced vasoconstriction, and phentolamine, an alpha-adrenoceptor blocking agent, plus propranolol was able to abolish it. Either of these prior applications resulted in a small but significant reduction of NT-induced vasoconstriction. These findings suggest that NT in plasma may function as a circulating hormone to exhibit an inhibitory action on the excitatory neural input to the rectum in the chicken, and that catecholamine release from adrenergic nerve terminals by NT may account for some but not all of the activity.

Animals↗
PubMed1981

Radiography of the distal colon and rectum after irradiation of carcinoma of the cervix.

High dose therapeutic irradiation for carcinoma of the cervix, usually delivered using a combination of external and intracavitary sources, may damage the rectum, sigmoid, distal small bowel, vagina, and urinary bladder. A pretreatment barium enema is valuable for baseline comparison should symptoms developing after treatment necessitate radiographic evaluation of the colon and rectum. Included in this review are a summary of radiation therapy techniques for carcinoma of the cervix, the radiation tolerance of normal pelvic structures, and the histopathology of changes in the bowel following irradiation. The spectrum of radiographic manifestations of radiation effect on the rectum and sigmoid is presented and contrasted with changes secondary to recurrent or persistent tumor. Gradations of symmetrical volume loss characterize radiation change, whereas mass effect, asymmetrical narrowing of the colon lumen, or fixation are more typical of tumor recurrence.

Aged↗
PubMed1980

Ulcerative colitis in childhood: should the rectum be preserved at surgery? Long-term results in 50 patients.

Fifty children subjected to surgery for ulcerative colitis were followed up for 9-23 (mean, 14) years. Of these, 22 had a colectomy and an ileorectal anastomosis, and 9 had a colectomy and an ileostomy with the rectum left in situ. Nineteen children with inflammatory changes in the rectum had a pancoloproctectomy and an ileostomy. The results of rectum-preserving operations were on the whole unsatisfactory. Most of the children made a good adjustment to life with an ileostomy. The high risk of malignancy in patients with an early onset of the disease makes pancoloproctectomy with ileostomy the method of choice even in children.

Adolescent↗